Water-soluble polyester resin containing phenylindan dicarboxylic acid

ABSTRACT

Alkyd resins which contain critical amounts of tall oil fatty acid and phenylindane dicarboxylic acid (PIDA) in combination with trimetllitic anhydride and trimethylol propane gives a resin which is dispersible in water, yet has exceptionally high mildew resistance, strength, hydrolytic stability, chemical resistance, film hardness, and excellent properties of fast drying and adhesion. The resin may be deposited in an electrophoresis bath if it is first solubilized by the addition of an alkaline material. The resin is self-curing and dries in air to a hard, durable, glossy film which does not require to be baked.

United States Patent Harris et al.

[54] WATER-SOLUBLE POLYESTER RESIN CONTAINING PHENYLINDAN DICARBOXYLICACID [72] Inventors: Robert R. Harris, Bumham, 11].; Carl H.

Kressman, Long Beach, Calif.

[73] Assignee: The Sherwin-Williams Company, Cleveland, Ohio [22] Filed:Dec. 14, 1970 211 App]. No.: 98,038

[52] US. Cl. ..260/22 M, 117/161 K, 260/29.2 E, 260/332 R, 260/975 [51]Int. Cl. ..C09d 3/64, C09d 5/14 [58] Field of Search... ..260/22, 97.5,75 R [56] References Cited UNITED STATES PATENTS 2,873,262 2/1959Petropoulos ..260/22 3,577,371 5/1971 Blair ..260/22 3,539,619 11/1970Steitz ..260/75 [451 May 30, 1972 OTHER PUBLlCATlONS Petropoulos,.l. C.,Novel Alkyd Resins," Oflicial Digest, 34, No. 452, pp. 992- 1,000, 1,002& 1,003 (1962).

Steitz et al., Phenylindan Dicarboxylic Acid: A New PolcondensationMonomer," Journal of Pain! Technology, Vol. 40, No. 524, 9/1968 pg. 384-388 Primary Examiner-Donald E. Czaja Assistant ExaminerRonald W. GrifiinAttomeyRichard G. Smith and Lowell G. Wise [57] ABSTRACT Alkyd resinswhich contain critical amounts of tall oil fatty acid and phenylindanedicarboxylic acid (PIDA) in combination with trimetllitic anhydride andtrimethylol propane gives a resin which is dispersible in water, yet hasexceptionally high mildew resistance, strength, hydrolytic stability,chemical resistance, film hardness, and excellent properties of fastdrying and adhesion. The resin may be deposited in an electrophoresisbath if it is first solubilized by the addition of an alkaline material.The resin is self-curing and dries in air to a hard, durable, glossyfilm which does not require to be baked.

4 Claims, No Drawings WATER-SOLUBLE POLYESTER RESIN CONTAININGPHENYLINDAN DICARBOXYLIC ACID BACKGROUND OF THE INVENTION Over the pastquarter of a century, water thinned vehicles have been developed andmarketed for use in air dried coatings. Generally, they have been usedfor interior flat wall paints, primarily because they exhibitedinadequate properties for acceptance in outdoor-protective usage. Morerecently water-dispersible paints have been used in outdoor-protectiveusage except that they are still subject to degradation by mildew andthey are characterized by inadequate hydrolytic stability, hardness andchemical resistance. Emulsion stability in particular has been a seriousproblem because the use of emulsifiers, wetting agents, buffers,thickeners, and protective colloids have often been entrapped in thefilm decreasing its adhesion to surfaces which are less than clean, andincreasing its sensitivity to the elements and to the attack by variousfungi.

Desirable resins are those which can be used like organic resinsolutions, are stable to agitation and which can be pigmented inconventional equipment. Preferably, a relatively high pigment-to-resinratio is desirable to give the film a high gloss with excellent hidingpower.

It is known that trimellitic anhydride (TMA) with propylene glycol andadipic acid can be cooked to give an alkali-ammonia-, orarnine-solubilizable resin which can be thinned to about 30 percentnon-volatile material and be used in an electrodeposition bath. Thedrawbacks of the TMA-propylene glycol-adipic acid resin are that, (1) itis extremely expensive, and, (2) it does not dry very well without beingbaked. The use of trimellitic anhydride in water-soluble baking resinsis disclosed in an article in the American Paint Journal, pages 71-84,June 20, 1960, by Benjamin Bolton and R. E. Van Strien.

It is known that PIDA is a versatile polycondensation monomer.Copolyesters with terephthalic acid and ethylene glycol containing up to30 percent by weight of PIDA can be drawn into fibers having goodproperties. It is also known that in air drying alkyds, PIDA contributesfaster drying rates and harder films than any of the phthalic acids atthe same oil length. Baking type alkyds cured with melamine resin havedemonstrated excellent heat, mechanical, and chemical resistance. Thesynthesis structure and property of various polyesters using PIDA havebeen discussed in an article entitled Phenylindan Dicarboxylic Acid: ANew Polycondensation Monomer" by Stitz and Knobloch Journal of PaintTechnology, Vol. 40, No. 524, September, 1968, pp. 384 to 393.Specifically, studies were made of a copolyester of PIDA andterephthalic acid with ethylene glycol in an effort to combine theproperties of the separate homopolymers because it would be desirable tohave a polymer with the crystallinity of polyethylene terphthalate andthe high second order transition temperature and low density ofpolyethylene phenylindan dicarboxylic. This prior art showed that theoptimum combination of properties occurs with up to 30 weight percent ofPlDA, after which the density of the polymers decreases. The instantresin which requires more than 30 percent by weight PIDA can be usedlike an organic resin solution, is stable to agitation and can bepigmented in conventional equipment. lt is particularly adapted toaccommodating a relatively high pigment resin ratio which is desirableto give the film a high gloss with excellent hiding power.

SUMMARY OF THE INVENTION It has been discovered that a water-solublepolyester resin, particularly useful in coatings which require tough,strong and durable films with high resistance to chemicals, moisture andmildew can be made from critical amounts of PIDA and tall oil, andappropriate amounts of trimethylol propane and trimellitic anhydridedetermined by the amounts of PIDA and tall oil used. The critical amountof PIDA is in the range from 31 to 45 percent and the critical amount ofoil is in the range from 51 to 30 percent.

PREFERRED EMBODIMENT OF THE INVENTION The instant water-soluble alkydresin is prepared by reacting from 30 to 51 percent by weight of anolefinically unsaturated carboxylic fatty acid having at least 10 carbonatoms, such as the vegetable and fish oils. More preferred are thevegetable oils and particularly tall oil and safilower oil. In view ofthe fact that tall and safilower oils are two of the softest drying oilsit is surprising and unexpected that they should be preferredingredients for the formation of exceptionally hard alkyd resins.

Another ingredient is phenylindan dicarboxylic acid (PIDA) the chemicalname of which is 1,1,3-trimethyl-5-carboxy-3(p-carboxyphenyl) indanwhich is used in an amount greater than 30 percent but less than 45percent by weight of the reaction mixture. Surprisingly, in view of theangularity of the PIDA molecule which pennits a high knuckle action,this rather large percentage of PIDA in the alkyd resin contributes toexceptional strength, toughness and fast drying rates of the film.

Another ingredient is a polyhydric alcohol. Amongst the polyhydricalcohols which may be used to form the instant alkyd resins are ethyleneglycol, diethylene glycol, trimethylene glycol, tetramethylene glycol,glycerol, trimethylol propane; 2,2-dimethylpropanedioll ,3; trimethylolpropane; 2,2-dimethylpropanedioll ,3;

trimethylol ethane; 2-ethyl-2-butyl-propanediol-l,3; pentaerythritol,dipentaerythritol, sorbitol, pinacol, arabitol, xylitol, adonitol,mannitol and the alkane diols such as butanedioll ,3; butanedioll ,4;pentanedioll ,5; hexanedioll ,6- and the like. These polyhydric alcoholsmay be used either singly or in combination with one another.

The last ingredient is a benzene tribasic acid, such as trimesic acid,hemimellitic acid, trimellitic acid and anhydrides thereof where suchanhydrides exist. Most preferred is trimellitic anhydride. Surprisinglythis substitution of trimellitic anhydride with a different acid such asdimethylol propionic acid does not give the drying times nor the extrememildew resistance that is obtained by benzene tribasic acids andparticularly trimellitic anhydride.

The process for making the instant alkyd resin comprises heating theolefinically unsaturated carboxylic acid to about 400 F under an inertgas blanket, and adding thereto the PIDA and the polyhydric alcohol andmaintaining heating until a desired acid number is reached. The reactionmass is cooled and the benzene tribasic acid or anhydride 'is added andthe temperature maintained below 400 F. Upon reaching the desired acidnumber the reaction mass is thinned in a suitable solvent and cooled.

The following examples describe the preparation of the instant alkydresin. All parts are parts by weight unless otherwise denoted.

EXAMPLE 1 3684 parts tall oil are placed in a reactor under an inert gasblanket and heated to 400 F. 22.38 parts trimethylol propane and 41.6parts PIDA are added to the reactor and homogeneously distributed to thetall oil while the reaction mass is heated to 480 F. The contents of thereactor are held for an acid number of 10-12, and then cooled to 380 F.7.03 parts trimellitic anhydride are added to the reaction mass and thetemperature maintained at 380 F until an acid number of from 48-52 isobtained. The reaction mass is then dropped into a thinning tank andthinned with a suitable solvent such as propoxy propanol to about 70percent non-volatile material and filtered.

Solubilization with an alkaline material such as ammonia,

an amine, or an alkali metal hydroxide permits dilution with water.

EXAMPLE 2 Films of the alkyd resin, the preparation of which isdescribed in Example 1 hereinabove, dried tack-free in 30 minutes. andattain a hardness of F (scale) after 24 hours. Immersion of an air driedfilm overnight in water at room temperature does not cause any filmdegradation. Adhesion tests run with a knife blade indicates that theadhesion of the alkyd resin is excellent and comparable to the bestavailable commercial alkyd resins particularly on surfaces which are notexceptionally clean.

In a test for mildew resistance the resin prepared as in Example 1hereinabove was tested against the best commercially available soya oilalkyd resins by a 12 month exterior exposure test at a 45 angle, facingSouth, in Florida. Using a rating system of l to 10, points indicatingno observable mildew attack, the PIDA alkyd enamel was rated 8 pointscompared to the commercial enamels which were about 3 points.

We claim:

1. An alkyd resin prepared by reacting 30 to 51 percent by weight of anoil containing an olefinically unsaturated carboxylic fatty acid havingat least 10 carbon atoms, with more than 30 percent but less than 45percent of phenylindan dicarboxylic acid and a sufficient amount of atrihydroxy polyol to provide an OH:COOH ratio in the range from about1.5 to about 2.5 and a sufi'lcient quantity of a benzene tribasic acidor anhydride to react with from 70 to about percent of the hydroxygroups present to form a water-dispersible alkyd resin capable of airdrying to a hard, glossy, durable finish without baking.

2. The resin of claim 1 wherein said oil is tall oil or safflower oil,said trihydroxy polyol is trimethylol propane and said benzene tribasicanhydride is trimellitic anhydride.

3. An alkyd resin prepared by reacting 30 to 51 percent by weight of anoil containing an olefinically unsaturated carboxylic fatty acid havingat least 10 carbon atoms, with more than 30 percent but less than 45percent of phenylindan dicarboxylic acid and a sufilcient amount of atrihydroxy polyol to provide an OH:COOH ratio in the range from about L5to about 2.5 and from about 5 to about 15 percent by weight andtrimellitic anhydride in the range from about 5 to about 15 percent byweight on a water-free basis.

4. The composition of claim 3 wherein said oil is tall oil or saffloweroil and said trihydroxy polyol is trimethylol propane.

2. The resin of claim 1 wherein said oil is tall oil or safflower oil,said trihydroxy polyol is trimethylol propane and said benzene tribasicanhydride is trimellitic anhydride.
 3. An alkyd resin prepared byreacting 30 to 51 percent by weight of an oil containing an olefinicallyunsaturated carboxylic fatty acid having at least 10 carbon atoms, withmore than 30 percent but less than 45 percent of phenylindandicarboxylic acid and a sufficient amount of a trihydroxy polyol toprovide an OH:COOH ratio in the range from about 1.5 to about 2.5 andfrom about 5 to about 15 percent by weight and trimellitic anhydride inthe range from about 5 to about 15 percent by weight on a water-freebasis.
 4. The composition of claim 3 wherein said oil is tall oil orsafflower oil and said trihydroxy polyol is trimethylol propane.